Airbag apparatus

ABSTRACT

An airbag apparatus having a retainer that can be employed with various embodiments of a horn switch that is turned on by the floating movement of a module cover. The apparatus includes an opening formed on a leg section of a module cover and a hook of a retainer, a predetermined gap is formed, thereby the module cover can be vertically moved. When the module cover is pressed, a horn switch is pressed so as to be turned on. Because a horn-switch supporting member is a separated part from the retainer, the retainer can be common to various models of the airbag apparatus having the module cover different in size and shape by changing only the horn-switch supporting member.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of thefollowing patent applications:

[0002] U.S. Provisional Application Ser. No. 60/176,025 filed Jan. 14,2000;

[0003] U.S. Provisional Application Ser. No. 60/182,907 filed Feb. 16,2000;

[0004] U.S. Provisional Application Ser. No. 60/186,745 filed Mar. 2,2000;

[0005] U.S. Provisional Application Ser. No. 60/190,013 filed Mar. 17,2000;

[0006] U.S. Provisional Application Ser. No. 60/207,190 filed May 26,2000;

[0007] U.S. Provisional Application Ser. No. 60/208,053 filed May 31,2000;

[0008] The above listed applications are incorporated by referenceherein in their entirety.

BACKGROUND

[0009] The present invention relates to an airbag apparatus having ahorn switch. More specifically, it relates to an airbag apparatusconfigured so that a horn switch is turned on only by actuation of amodule cover when the airbag is pressed.

[0010] A driver-side airbag apparatus arranged in a steering wheel maybe designed to include a module cover that when pressed, activates ahorn switch so as to sound a horn. When the airbag apparatus is formedsuch that not the entire airbag apparatus but only the module cover isto be actuated, the pushing force for turning on the horn switch can besmall.

[0011] An airbag apparatus 100 having such a structure is shown in FIG.29. The airbag apparatus 100 comprises a retainer 102, an airbag 106attached to the retainer 102 with an airbag fitting ring 104, aninflator 108 for inflating the airbag 106, and a module cover 110 forcovering the folded airbag 106.

[0012] An integral leg section 112 protrudes from the back side of themodule cover 110, and hooks 116 of a side-wall section 114 which is bentforward from the retainer 102 are inserted through openings 118 in theleg section 112. Each hook 116 outwardly protrudes from the side-wallsection 114 in an L-shape.

[0013] The inflator 108 includes a flange 108 a. Bolts 120 protrudingfrom the ring 104 are inserted through the retainer 102 and the flange108 a, so that the inflator 108 is fixed to the retainer 102 togetherwith the airbag 106 by tightening nuts 122.

[0014] The shape of the folded airbag 106 is maintained by a shapeholding member 124. The shape holding member 124 allows the airbag 106to expand by breaking-off or deforming when the airbag 106 is inflated.

[0015] A bracket 132 protrudes upwardly from a steering wheel 130, andprojecting pieces 134 protruding downward from the backside of theretainer 102. The pieces 134 are fixed to the bracket 132 with bolts 136and nuts 138.

[0016] A predetermined sized gap is formed between the back face of themodule cover 110 and the shape holding member 124. A predetermined sizedgap is also formed between the opening 118 formed on the leg section 112of the module cover 110 and the hook 116. As a result, the module cover110 can be moved vertically when viewing FIG. 29. When the module cover110 is pressed, a horn switch (not shown) is pressed so as to be turnedon. The horn switch is integrally formed with the retainer 102 andattached to an extending portion extending from the retainer 102.

[0017] In case that a horn switch is attached to the extending portionformed integrally with a retainer as in the airbag apparatus shown inFIG. 29, when the shape of module cover and the position of horn switchdiffer in each airbag apparatus, the retainer is required to be designedcorresponding to the module cover shape and the horn switch position ofeach airbag apparatus, adding significant cost and inconvenience to themanufacturing and design processes.

SUMMARY OF THE INVENTION

[0018] It is an object of the present invention to provide an airbagapparatus capable of having a retainer in common to various models of anairbag apparatus which include a horn switch that is turned on by movinga module cover back and forth.

[0019] An airbag apparatus according to the present invention comprises:an airbag; a retainer having the airbag attached thereto; a module covercovering the airbag and being movable and extending toward the retainer;a horn-switch supporting member which is a separate part from theretainer; and a horn switch which is supported by the horn-switchsupporting member and which is turned on by the approaching movement ofthe module cover toward the retainer.

[0020] In such an airbag apparatus, even if the position of the hornswitch differs in each airbag apparatus, the common retainer can be usedby changing only the horn-switch supporting member.

[0021] In addition, it is preferable that an engagement portion or lowerengagement mechanism for positioning the horn-switch supporting memberrelative to the retainer be provided so that the degree of accuracy ofmounting the horn-switch supporting member be improved and efficiency ofthe mounting work be increased.

[0022] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only, and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] These and other features, aspects, and advantages of the presentinvention will become apparent from the following description, appendedclaims, and the accompanying exemplary embodiments shown in thedrawings, which are briefly described below.

[0024]FIG. 1 is a sectional view of an airbag apparatus according to anembodiment of the present invention.

[0025]FIG. 2 is an assembly view of the airbag apparatus according tothe embodiment at FIG. 1.

[0026]FIG. 3 is an assembly view of a horn switch.

[0027] FIGS. 4(a) and 4(b) are sectional views of the horn switch.

[0028]FIG. 5 is an assembly view of a horn switch.

[0029]FIG. 6 is a sectional view of a horn switch.

[0030]FIG. 7 is an assembly view of the horn switch.

[0031]FIG. 8 is an assembly view of a horn switch.

[0032]FIG. 9 is a sectional view of a horn switch.

[0033]FIG. 10 is a sectional view of a horn switch.

[0034]FIG. 11 is an assembly view of the horn switch.

[0035]FIG. 12 is a sectional view of a horn switch.

[0036]FIG. 13 is a sectional view of a horn switch.

[0037]FIG. 14 is a sectional view of a horn switch.

[0038]FIG. 15 is a sectional view of a spring for a horn switch.

[0039] FIGS. 16(a) and 16(b) are sectional views of an airbag apparatusin the vicinity of a horn switch.

[0040] FIGS. 17(a) and 17(b) are sectional views of an airbag apparatusin the vicinity of a horn switch.

[0041]FIG. 18 is an assembly view for showing an engaging relationshipbetween a horn-switch supporting member and a retainer.

[0042] FIGS. 19(a) and 19(b) are a sectional view and an assembly viewshowing an engaging relationship between the horn-switch supportingmember and the retainer.

[0043]FIG. 20 is an assembly view for showing an engaging relationshipbetween the horn-switch supporting member and the retainer.

[0044]FIG. 21 is an assembly view for showing an engaging relationshipbetween the horn-switch supporting member and the retainer.

[0045]FIG. 22 is an assembly view for showing an engaging relationshipbetween the horn-switch supporting member and the retainer.

[0046]FIG. 23 is an assembly view for showing an engaging relationshipbetween the horn-switch supporting member and a steering wheel.

[0047]FIG. 24 is an assembly view for showing an engaging relationshipbetween the horn-switch supporting member and the steering wheel.

[0048]FIG. 25 is an assembly view for showing an engaging relationshipbetween the horn-switch supporting member and the steering wheel.

[0049] FIGS. 26(a)-26(e) are perspective views showing examples of theprojection structure.

[0050]FIG. 27 is an assembly view for showing an engaging relationshipbetween the horn-switch supporting member and the steering wheel.

[0051]FIG. 28 is a sectional view for showing a different engagingrelationship between a module cover and the retainer.

[0052]FIG. 29 is a sectional view of a module-cover-floating type airbagapparatus.

DETAILED DESCRIPTION

[0053] Although references are made below to directions, such as left,right, up, down, etc., in describing the drawings, they are maderelative to the drawings (as normally viewed) for convenience. Thesedirections are not intended to be taken literally or limit the presentinvention in any form.

[0054] Exemplary embodiments of the invention will be described belowwith reference to the drawings. FIG. 1 is a sectional view of an airbagapparatus according to an embodiment; FIG. 2 is an assembly view of theairbag apparatus (an air bag is not shown for illustrating clearly);FIG. 3 is an assembly view of a horn switch; and FIG. 4 is a sectionalview of the horn switch.

[0055] An airbag apparatus 1 comprises a retainer 2, an airbag 3attached to the retainer 2 with an airbag fitting ring 4, an inflator 6for inflating the airbag 3, and a module cover 5 for covering the foldedairbag 3. The shape of the folded airbag 3 is maintained by a shapeholding member 18.

[0056] As shown in FIG. 2, a leg section 5L integrally protrudes fromthe back side of the module cover 5, and hooks 2F of a side-wall section2S, which is bent forward from the retainer 2, are inserted throughopenings 5 a in the leg section 5L. The hook 2F protrudes outward fromthe side-wall section 2S in an L-shape.

[0057] The inflator 6 has a flange 6 a, and bolts 15 protruding from thering 4 are inserted through the retainer 2 and the flange 6 a, so thatthe inflator 6 is fixed to the retainer 2 together with the airbag 3 bytightening nuts 16.

[0058] From a steering wheel 10, a bracket 11 protrudes upward whenviewing FIG. 1, and base portions 8 a of a horn-switch supporting member8 and projecting pieces 9 protruding downward from the back side of theretainer 2 are fixed to the bracket 11 with bolts 12. In the baseportion 8 a and the projecting piece 9, openings 8 c and 9 b to beinserted by the bolt 12 are respectively formed. The bolt 12 is screwedinto a tapped hole formed on the bracket 11. At the tip of theprojecting piece 9, a lug 9 a for receiving and positioning the baseportion 8 a is formed by bending.

[0059] A horn switch 20 lies between an upper portion 8 b of thehorn-switch supporting member 8 and the module cover 5. The upperportion 8 b extends in the direction orthogonal to theback-and-forth-moving direction of the module cover 5.

[0060] Between the shape holding member 18 and the module cover 5, apredetermined gap is formed. A predetermined gap is also formed betweenthe opening 5 a formed on the leg section 5L of the module cover 5 andthe hook 2F. As a result, the module cover 5 can be vertically movedwhen viewing FIG. 1. When the module cover 5 is pressed, the horn switch20 is pressed so as to be turned on.

[0061] As shown in FIGS. 3 and 4, the horn switch 20 preferablycomprises a contact member 21, a coil spring 22, and a spring guide 23fitted inside the spring 22.

[0062] A hole 25 is formed in the contact member 21. A projecting pin 24which protrudes from the module cover 5 may be deposited in the hole 25.The contact member 21 is fixed to the module cover 5 by depositing thetip of the projecting pin 24 after the projecting pin 24 is insertedinto the hole 25.

[0063] In the contact member 21, a contact 26 formed of a projection andan opening 27 for retaining a head portion 23 a of the guide 23 areformed. When the module cover 5 is pressed, the contact 26 abuts theupper portion 8 b of the horn-switch supporting member 8, so that thehorn switch 20 is turned on so as to sound a horn.

[0064] As shown in FIG. 4(a), the spring guide 23 is retained in theopening 27 at the head portion 23 a while a pair of elastic legs 23 b inthe base side thereof are retained in an opening 28 on the upper portion8 b of the horn-switch supporting member 8. The legs 23 b areelastically deformable in directions approaching to and separating fromeach other. Projections 23 c are formed on the opposite faces to theopposing faces of the legs 23 b, and the projections 23 c are retainedby the upper portion 8 b surrounding the opening 28.

[0065] The spring guide 23 may function as an insulator between thesupporting member 8 and the contact member 21. Furthermore, the guide 23is configured to properly align the contact member 21 and supportingmember 8 with the module cover 5, thereby ensuring proper operation ofthe switch. Due to the multiple functions of the guide 23 the switch maybe configured with fewer parts resulting in a vast improvement over theprior art.

[0066] When the airbag 3 is inflated so that the module cover 5 is tornand opened along a tearing line 5 a, a great force is applied to thehorn switch 20 from the module cover 5 in the direction separating fromthe supporting member 8. At this time, the legs 23 b come out of theopening 28. Then, when the module cover 5 abuts an occupant, as shown inFIG. 4(b), the pair of legs 23 b are deformed astride along the top faceof the upper portion 8 b of the supporting member 8 so as to maintainthe gap between the contact 26 and the horn-switch supporting member 8,thereby preventing the horn switch 20 from being turned on.

[0067] In the airbag apparatus according to the present invention, thehorn-switch supporting member 8 is a separated part from the retainer 2.Thus, the retainer 2 can be common to various models of the airbagapparatus having the module cover 5 different in size and shape bychanging only the horn-switch supporting member 8.

[0068]FIG. 5 is a perspective view of another horn switch according tothe present invention. In the horn switch 20A, U-shaped brackets 21 aare formed in a contact member 21A and are retained to vertical wallportions 29 formed in a module cover 5A. In the bracket 21 a, a hook 21b is formed, and the contact member 21A is fixed to the module cover 5Aby engaging the hook 21 b into the vertical wall portion 29. The otherstructures of the horn switch shown in FIG. 5 are the same as thoseshown in FIG. 3. Throughout the application, like reference numeralsdesignate like structures.

[0069]FIG. 6 is a sectional view of another embodiment of a horn switchaccording to the present invention, and FIG. 7 is an assembly viewthereof. The horn switch 30 comprises a switch plate 31 held by a modulecover 5B, an insulating plate 32 attached to the upper portion 8 b ofthe horn-switch supporting member 8 so as to oppose the switch plate 31,a fixed contact 33 fixed to the horn-switch supporting member 8 so as topenetrate through the insulating plate 32, a spring 34, and a pair ofprojecting pieces 35 united with the module cover 5B.

[0070] The switch plate 31 is held by convex portions 35 a protrudingfrom base sides of the projecting pieces 35, as shown in FIG. 6. Thespring 34 lies between the insulating plate 32 and the switch plate 31.Hooks 35 b formed at tips of the projecting pieces 35 are retained inopenings 36 formed on the horn-switch supporting member 8. When themodule cover 5B is pressed, the tip of the switch plate 31 abuts thecontact 33, so that the horn switch 30 is turned on so as to sound ahorn.

[0071]FIG. 8 is an assembly view showing a structural example of stillanother embodiment of a horn switch according to the present invention.The horn switch 30A comprises a switch plate 31A, the spring 34, aninsulating plate 32A, and the contact 33. The switch plate 31A is fittedinside a cylindrical body 37 formed in the module cover as far as theswitch plate 31A abuts stoppers 37 b. In the insulating plate 32A,plural extending pieces 32 a (three pieces in this case) are formed.Convex portions 32 b of the extending pieces 32 a are brought intoengagement with elongated holes 37 a of the cylindrical body 37. Theinsulating plate 32A is fixed to the upper portion 8 b of thehorn-switch supporting member 8 by engaging convex portions 32 c formedon the base of the insulating plate 32A with openings 36 a of the upperportion 8 b. When the module cover is pressed, a convex portion of theswitch plate 31A abuts the contact 33, so that the horn switch 30A isturned on.

[0072] The extending pieces 32 a are arranged in the external peripheryof the cylindrical body 37, as shown in FIG. 8. Alternately, as shown inFIG. 9, an insulating plate 32A′ of a horn switch 30B may be providedthat provides for the extending pieces 32 a to be arranged along theinternal periphery of the cylindrical body 37. The convex portions 32 bare brought into engagement with a circumferential projection 37 c inthe internal periphery at the lower end of the cylindrical body 37. Theswitch plate 31A is fitted around a projecting portion 5 d of a modulecover 5D. A connector 31 a may be provided to link the switch plate 31Ato external circuitry and equipment including, for example, the vehiclehorn. The other reference characters shown in FIG. 9 designate likecommon portions shown in FIG. 8.

[0073]FIGS. 10 and 11 are sectional and assembly views respectively forshowing a structural example of a further horn switch according toanother alternative embodiment of the present invention.

[0074] The horn switch 40 comprises a switch plate 41 held by a modulecover 5C, a spring 42, an insulating block 43, and a contact 44 disposedin the insulating block 43. From the module cover 5C, a square portion45 protrudes, so that the switch plate 41 is inserted through slots 45 aformed on a pair of opposing faces of the square tubular portion 45. Inaddition, the insulating block 43 is ⊃-shaped (or C-shaped) when viewingthe side thereof, and into a space 43 a equivalent to the intermediateof the ⊃-shaped portion, the switch plate 41 is inserted. A spring 42lies between the top face of the insulating block 43 and the modulecover 5C.

[0075] A pair of leg pieces 43 b protruding from the bottom face of theinsulating block 43 are brought into engagement with openings 46 on theupper portion 8 b of the horn-switch supporting member 8. When themodule cover SC is pressed, the switch plate 41 abuts the contact 44, sothat the horn switch 40 is turned on.

[0076] A horn switch 47 shown in FIG. 12 comprises a guide shaft 49arranged inside a cylindrical portion 48 disposed in a module cover 5E.A spring 51 lies between a cap 49 a at the head of the guide shaft 49and a switch plate 50. An insulating body 52 lies between the switchplate 50 and the horn-switch supporting member 8.

[0077] The guide shaft 49 penetrates through the insulating body 52 andthe switch plate 50. At the lower end of the guide shaft 49, a stoppernut 53 is fixed, and the stopper nut 53 abuts a lower flange 52 a of theinsulating body 52. The external peripheral portion of the switch plate50 extends outwardly off the insulating body 52, and is elasticallydeformable.

[0078] When the module cover 5E is pressed, the cylindrical portion 48lowers the external periphery of the switch plate 50 forcing it tocontact the horn-switch supporting member 8, and the horn switch 47 isthereby closed or turned on.

[0079] In a horn switch 55 shown in FIG. 13, the upper end of a metallicguide shaft 56 serves as a contact member and is fixed to a module cover5F. On the horn-switch supporting member 8, an insulating plate 57 isattached. A cylindrical portion 58 protrudes from the insulating plate57. Inside the cylindrical portion 58, the horn-switch supporting member8 is exposed. Between a projection 58 a on the internal peripheral faceof the cylindrical portion 58 and a projection 56 a on the internalperipheral face of a lower portion of the guide shaft 56, a tension coilspring 59 is hung. When the module cover 5F is pressed, the coil spring59 is stretched so that the guide shaft 56 abuts the horn-switchsupporting member 8, and the horn switch 55 is thereby turned on.

[0080] A horn switch 60 shown in FIG. 14 comprises a switch plate 62fitted into a cylindrical portion 61 protruding from a module cover 5G.The switch plate 62 comprises a truncated conical portion 62 a insertedinto the cylindrical portion 61, an external annular portion 62 barranged along the external peripheral face of the cylindrical portion61, and hooks 62 c disposed in the external annular portion 62 b.Theswitch plate 62 is fixed to the cylindrical portion 61 by engaging thehooks 62 c into the external peripheral face of the cylindrical portion61. A truncated conical insulating cap 63 is fitted into the truncatedconical portion 62 a of the switch plate 62. A spring 64 lies betweenthe cap 63 and the horn-switch supporting member 8.

[0081] When the module cover 5G is pressed, the horn-switch supportingmember 8 abuts a contact portion 62 d of the switch plate 62, and thehorn switch 60 is thereby turned on.

[0082] The insulating cap 63 is used in the horn switch shown in FIG.14. However, the insulating cap 63 may be omitted as long as a spring64A having an insulating film 64 b formed on the surface of a springbody 64 a is used, as shown in FIG. 15.

[0083] A horn switch 65 shown in FIG. 16 comprises a switch plate 66attached to a module cover 5H and a contact 67 disposed in thehorn-switch supporting member 8. On the module cover 5H, a guide shaft68 is projectingly formed in the vicinity of the horn switch 65. Anenlarged conical head 69 a at the lower end of the guide shaft 68 isbrought into engagement with a lower fringe of an opening 69 on thehorn-switch supporting member 8. A coil spring 70 lies so as to surroundthe guide shaft 68 between the module cover 5H and the horn-switchsupporting member 8. The spring 70 is welded to the horn-switchsupporting member 8. When the module cover 5H is pressed, the switchplate 66 abuts the contact 67, and the horn switch 65 is thereby turnedon. FIG. 16(b) is a sectional view at the line B-B of FIG. 16(a).

[0084] As shown in FIG. 17(a) and 17(b), module cover 5H may includeguide plates 71 or guide plates 71A projectingly formed on both sides ofthe switch plate 66. In FIG. 17(a), the guide plate 71 comprises anopening 71 a, and projecting tongue-like portions 71 b on both sides ofthe horn-switch supporting member 8 are brought into engagement with theopenings 71 a. In FIG. 17(b), hooks 71 c formed at the lower ends of theguide plates 71A are brought into engagement with both sides of thehorn-switch supporting member 8. FIG. 17(a) and (b) shows the samesections as those shown in FIG. 16(b).

[0085] Regarding the aforementioned examples of horn switches, weldingmay be used to connect the vertical wall portions of the module cover toa portion of the contact member.

[0086] Referring to FIGS. 18 to 22, different engaging examples betweenthe retainer 2 and the horn-switch supporting member 8 (i.e., a lowerengagement mechanism) will be described.

[0087] In FIG. 18, a projection 75 is formed in a base portion 8 a ofthe horn-switch supporting member 8 and is brought into engagement withan opening 74 on the projecting piece 9 of the retainer 2, therebypositioning the horn-switch supporting member 8.

[0088] In FIG. 19(a), (b), the opening 74 is omitted and the horn-switchsupporting member 8 is positioned by retaining a projection 76 in thebase portion 8 a to a corner of the upper fringe of the retainer 2.Although, the horn switch 21A is shown in FIG. 19, any one of the hornswitches mentioned above may be used. FIG. 19(b) is an assembly viewshowing the engaging relationship between the horn switch and theretainer. FIG. 19(a) is a sectional view of an essential part of theairbag apparatus having the structure shown in FIG. 19(b).

[0089] As shown in FIG. 20, a rising piece 77 may be formed at the lowerend of the projecting piece 9 of the retainer 2. A slit or slot 78 maybe formed at the root of the rising piece 77. A projection 79 formed atthe tip of the base portion 8 a in the horn-switch supporting member 8is brought into engagement with the slit 78, thereby positioning thehorn-switch supporting member 8.

[0090] As shown in FIG. 21, ribs 80 may be erected along the both sidesof the projection piece 9, and steps 81 formed in both sides of the baseportion 8 a may be abutted to the upper ends of the ribs 80, so that thehorn-switch supporting member 8 is positioned.

[0091] As shown in FIG. 22, ribs 82 may be erected along the both sidesof the base portion 8 a, and steps 83 formed in both sides of theprojection piece 9 may be abutted to the ribs 82, so that thehorn-switch supporting member 8 is positioned.

[0092] In addition, as shown in FIG. 19(a), the tip of the upper portion8 b of the horn-switch supporting member 8 may be abutted to a step ofthe steering wheel 10, and the upper portion 8 b of the horn-switchsupporting member 8 is thereby positioned.

[0093] Referring to FIGS. 23 to 27, other positioning examples of theupper portion of the supporting member 8 b relative to the steeringwheel 10 (i.e., an upper engagement mechanism) will be described.

[0094] In FIG. 23, a concave portion 85 is formed in the steering wheel10, and the tip of the upper portion 8 b of the horn-switch supportingmember 8 is brought into engagement with the concave portion 85 so as toposition the horn-switch supporting member 8.

[0095] In FIG. 24, ribs 86 are erected along the both sides of the endportion in the base portion 8 a and abutted on vertical wall faces ofthe concave portion 85.

[0096] In FIG. 25, a projection 87 is formed on the bottom face of theconcave portion 85 and fitted into a small hole 88 formed in the upperportion 8 b of the horn-switch supporting member 8. In FIG. 25, theprojection 87 is circular column-shaped; however, projections 87A to 87Ehaving various shapes as shown in FIGS. 26(a) to 26(e) may be used. Theprojection 87A is tapered so as to engage with the small hole 88tightly.

[0097] All the projections 87B, 87C, 87D, and 87E have enlarged portions87 b, 87 c, 87 d, and 87 e at their end portions, respectively, and wheneach of the projections 87B to 87E is once fitted into the small hole88, coming-off can be prevented due to the enlarged portions 87 b to 87e.

[0098] In FIG. 27, the end of the horn-switch supporting member 8 isfitted into a space surrounded by three projection pieces 89.

[0099] In the present invention, as shown in FIG. 28, an L-shaped hookfitting 90 may be attached to the leg section 5L of the module coverwith a rivet, etc., so as to engage the hook fitting 90 with the end ofthe horn-switch supporting member 8.

[0100] As described above, in the airbag apparatus according to thepresent invention wherein only the module cover floats so as to turn thehorn switch on, the retainer can be common to various models of theairbag apparatus. The horn-switch supporting member is sufficient tohave a low strength, so that the weight of the apparatus can be reduced.

[0101] Given the disclosure of the present invention, one versed in theart would appreciate that there may be other embodiments andmodifications within the scope and spirit of the invention. For example,in the embodiments described above, the coil spring is adopted for thehorn switch; however, a leaf spring, etc., may be used.

[0102] Accordingly, all modifications attainable by one versed in theart from the present disclosure within the scope and spirit of thepresent invention are to be included as further embodiments of thepresent invention. The scope of the present invention is to be definedas set forth in the following claims.

We claim:
 1. An airbag apparatus comprising: a retainer member having anairbag attached thereto; a module cover covering said airbag and beingmovable toward said retainer; a supporting member separate from theretainer and configured to be engaged with the retainer the supportingmember providing support for an electrical switch, wherein theelectrical switch is configured to close by the movement of the modulecover toward said retainer.
 2. The airbag apparatus of claim 1 , furthercomprising a lower engagement mechanism for positioning the supportingmember relative to the retainer.
 3. The airbag apparatus of claim 2 ,wherein the lower engagement mechanism comprises a projection on thesupporting member that engages an opening on the retainer member.
 4. Theairbag apparatus of claim 2 , wherein the lower engagement mechanismcomprises a projection on the supporting member positioned to overlie acorner of the retainer member.
 5. The airbag apparatus of claim 2 ,wherein the supporting member and the retainer member are secured to asupport bracket by a common fastener.
 6. The airbag apparatus of claim 2, wherein the lower engagement mechanism comprises a slot formed in theretainer member and a tap formed in the supporting member.
 7. The airbagapparatus of claim 2 , wherein the lower engagement mechanism comprisesa pair of ribs on the retainer member, wherein each rib extends towardthe supporting member and engages the supporting member adjacent a stepin the supporting member.
 8. The airbag apparatus of claim 2 , whereinthe lower engagement mechansim comprises a pair of ribs on thesupporting member, wherein each rib extends toward the retainer memberand engages the retaininer member adjacent a step in the retainermember.
 9. The airbag apparatus of claim 1 , wherein the airbagapparatus is postioned in a steering wheel assembly including a steeringwheel.
 10. The airbag apparatus of claim 9 , wherein the supportingmember engages the steering wheel.
 11. The airbag apparatus of claim 10, further comprising an upper engagement mechanism for positioning thesupporting member relative to the steering wheel.
 12. The airbagapparatus of claim 11 , wherein the upper engagement mechanism comprisesa concave portion formed in the steering wheel adapted to engage an endportion of the supporting member.
 13. The airbag apparatus of claim 12 ,wherein the end portion of the supporting member comprises a pair ofribs, wherein each rib abuts a vertical wall face of the concaveportion.
 14. The airbag apparatus of claim 13 , wherein the concaveportion includes a projection configured to engage a hole located on theend portion of the supporting memember.
 15. The airbag apparatus ofclaim 14 , wherein the projection includes an enlarged end portion. 16.The airbag apparatus of claim 11 , wherein the upper engagementmechanism comprises a plurality of projections positioned on thesteering wheel so that an end portion of the supporting member issurrounded by the projections when it engages the steering wheel. 17.The airbag apparatus of claim 1 , wherein the supporting member engagesthe module cover.
 18. An electrical switch assembly located within asteering wheel assembly for use with an electrical switch for a vehiclehorn activation circuit, the switch assembly comprising: an electricalcontact mounted on a movable contact member connected to the steeringwheel; a switch supporting member positioned so that when the contactmember moves toward the supporting member, the electrical contact makescontact with the supporting member to thereby close the switch; a springpositioned for biasing the electrical contact away from the supportingmember; and a guide for maintaining the spring in position.
 19. Theswitch assembly of claim 18 , wherein the spring is positioned betweenthe contact member and the supporting member.
 20. The switch assembly ofclaim 18 , wherein the contact member is connected to a module cover forthe steering wheel.
 21. The switch assembly of claim 18 , wherein theguide is surrounded by the spring.
 22. The switch assembly of claim 18 ,wherein the guide surrounds the spring.
 23. The switch assembly of claim18 , wherein the guide is secured to the supporting member.
 24. Theswitch assembly of claim 23 , wherein the guide is secured to thecontact member and is configured to align the contact member relative tothe steering wheel.
 25. The switch assembly of claim 20 , wherein thecontact member includes U-shaped brackets for receiving projectingportions of the module cover.
 26. The switch assembly of claim 25 ,wherein the contact comprises the brackets.
 27. The switch assembly ofclaim 18 , wherein the supporting member is attached to an air bagretainer.
 28. The switch assembly of claim 18 , further comprising aninsulating member.
 29. The switch assembly of claim 28 , wherein theinsulating member is positioned between the contact member and thesupporting member.
 30. The switch assembly of claim 28 , wherein thecontact member is elastically deformable.
 31. The switch assembly ofclaim 28 , wherein the insulating member comprise the guide.
 32. Theswitch assembly of claim 31 , wherein the contact member is positionedso that movement of a module cover for the steering wheel bends thecontact member to contact the supporting member.
 33. The switch assemblyof claim 18 , further comprising a module cover for the steering wheel,wherein the guide is integrally formed with the module cover.
 34. Anelectrical switch assembly located within a steering wheel assembly foruse with an electrical switch for a vehicle horn activation circuit, theswitch assembly comprising: a movable contact member connected to thesteering wheel; an electrical contact mounted on a switch supportingmember positioned so that when the contact member moves toward thesupporting member, the electrical contact makes contact with the contactmember to thereby close the switch; a spring positioned to biasing theelectrical contact away from the contact member; and a guide formaintaining the spring in position.
 35. The switch assembly of claim 34, further comprising an insulation member.
 36. The switch assembly ofclaim 35 , wherein the insulation member comprises a plate.
 37. Theswitch assembly of claim 34 , wherein the contact member is secured to amodule cover for the steering wheel.
 38. The switch assembly of claim 37, wherein the guide is integrally formed with the module cover.
 39. Theswitch assembly of claim 35 , wherein the guide comprises the insulationmember.
 40. The switch assembly of claim 37 , wherein the contact memberis fitted inside a cylindrical body formed in the module cover.
 41. Theswitch assembly of claim 35 , wherein the insulation member ispositioned between the contact and the supporting member.
 42. The switchassembly of claim 34 , wherein the switch supporting member is attachedto an airbag retainer.
 43. The switch assembly of claim 35 , wherein theinsulation member comprises a c-shaped insulating block.
 44. The switchassembly of claim 43 , wherein the contact member and the contact arelocated within the opening of the c-shaped insulating block.
 45. Theswitch assembly of claim 43 , wherein the contact member is secured to amodule cover for the steering wheel and the spring is positioned betweenthe insulating block and the module cover.
 46. The switch assembly ofclaim 38 , wherein the module cover includes a projection having arectangular cross-section, the spring being positioned within theprojection.